// SimpleDirectX.cpp : Defines the exported functions for the DLL application.
//

// SimpleDX.cpp : Defines the exported functions for the DLL application.
//

#include "stdafx.h"
#include "SimpleDirectX.h"
#include <d3d9.h>
#pragma warning( disable : 4996 ) // disable deprecated warning 
#include <strsafe.h>
#pragma warning( default : 4996 )

//-----------------------------------------------------------------------------
// Global variables
//-----------------------------------------------------------------------------
LPDIRECT3D9             g_pD3D = NULL; // Used to create the D3DDevice
LPDIRECT3DDEVICE9       g_pd3dDevice = NULL; // Our rendering device
LPDIRECT3DVERTEXBUFFER9 g_pVB = NULL; // Buffer to hold Vertices

// A structure for our custom vertex type
struct CUSTOMVERTEX
{
    FLOAT x, y, z, rhw; // The transformed position for the vertex
    DWORD color;        // The vertex color
};

// Our custom FVF, which describes our custom vertex structure
#define D3DFVF_CUSTOMVERTEX (D3DFVF_XYZRHW|D3DFVF_DIFFUSE)

//-----------------------------------------------------------------------------
// Name: InitD3D()
// Desc: Initializes Direct3D
//-----------------------------------------------------------------------------
void InitD3D( HWND hWnd )
{
    // Create the D3D object.
    if( NULL == ( g_pD3D = Direct3DCreate9( D3D_SDK_VERSION ) ) )
        return;

    // Set up the structure used to create the D3DDevice
    D3DPRESENT_PARAMETERS d3dpp;
    ZeroMemory( &d3dpp, sizeof( d3dpp ) );
    d3dpp.Windowed = TRUE;
    d3dpp.SwapEffect = D3DSWAPEFFECT_DISCARD;
    d3dpp.BackBufferFormat = D3DFMT_UNKNOWN;

    // Create the D3DDevice
    if( FAILED( g_pD3D->CreateDevice( D3DADAPTER_DEFAULT, D3DDEVTYPE_HAL, hWnd,
                                      D3DCREATE_SOFTWARE_VERTEXPROCESSING,
                                      &d3dpp, &g_pd3dDevice ) ) )
    {
        return;
    }

    // Device state would normally be set here
}




//-----------------------------------------------------------------------------
// Name: InitVB()
// Desc: Creates a vertex buffer and fills it with our Vertices. The vertex
//       buffer is basically just a chuck of memory that holds Vertices. After
//       creating it, we must Lock()/Unlock() it to fill it. For indices, D3D
//       also uses index buffers. The special thing about vertex and index
//       buffers is that they can be created in device memory, allowing some
//       cards to process them in hardware, resulting in a dramatic
//       performance gain.
//-----------------------------------------------------------------------------
void InitVB()
{
    // Initialize three Vertices for rendering a triangle
    CUSTOMVERTEX Vertices[] =
    {
        { 150.0f,  50.0f, 0.5f, 1.0f, 0xffff0000, }, // x, y, z, rhw, color
        { 250.0f, 250.0f, 0.5f, 1.0f, 0xff00ff00, },
        {  50.0f, 250.0f, 0.5f, 1.0f, 0xff00ffff, },
    };

    // Create the vertex buffer. Here we are allocating enough memory
    // (from the default pool) to hold all our 3 custom Vertices. We also
    // specify the FVF, so the vertex buffer knows what data it contains.
    if( FAILED( g_pd3dDevice->CreateVertexBuffer( 3 * sizeof( CUSTOMVERTEX ),
                                                  0, D3DFVF_CUSTOMVERTEX,
                                                  D3DPOOL_DEFAULT, &g_pVB, NULL ) ) )
    {
        return ;
    }

    // Now we fill the vertex buffer. To do this, we need to Lock() the VB to
    // gain access to the Vertices. This mechanism is required becuase vertex
    // buffers may be in device memory.
    VOID* pVertices;
    if( FAILED( g_pVB->Lock( 0, sizeof( Vertices ), ( void** )&pVertices, 0 ) ) )
        return ;
    memcpy( pVertices, Vertices, sizeof( Vertices ) );
    g_pVB->Unlock();

}




//-----------------------------------------------------------------------------
// Name: Cleanup()
// Desc: Releases all previously initialized objects
//-----------------------------------------------------------------------------
VOID Cleanup()
{
    if( g_pVB != NULL )
        g_pVB->Release();

    if( g_pd3dDevice != NULL )
        g_pd3dDevice->Release();

    if( g_pD3D != NULL )
        g_pD3D->Release();
}




//-----------------------------------------------------------------------------
// Name: Render()
// Desc: Draws the scene
//-----------------------------------------------------------------------------
VOID Render()
{
    // Clear the backbuffer to a blue color
    g_pd3dDevice->Clear( 0, NULL, D3DCLEAR_TARGET, D3DCOLOR_XRGB( 0, 0, 255 ), 1.0f, 0 );

    // Begin the scene
    if( SUCCEEDED( g_pd3dDevice->BeginScene() ) )
    {
        // Draw the triangles in the vertex buffer. This is broken into a few
        // steps. We are passing the Vertices down a "stream", so first we need
        // to specify the source of that stream, which is our vertex buffer. Then
        // we need to let D3D know what vertex shader to use. Full, custom vertex
        // shaders are an advanced topic, but in most cases the vertex shader is
        // just the FVF, so that D3D knows what type of Vertices we are dealing
        // with. Finally, we call DrawPrimitive() which does the actual rendering
        // of our geometry (in this case, just one triangle).
        g_pd3dDevice->SetStreamSource( 0, g_pVB, 0, sizeof( CUSTOMVERTEX ) );
        g_pd3dDevice->SetFVF( D3DFVF_CUSTOMVERTEX );
        g_pd3dDevice->DrawPrimitive( D3DPT_TRIANGLELIST, 0, 1 );

        // End the scene
        g_pd3dDevice->EndScene();
    }

    // Present the backbuffer contents to the display
    g_pd3dDevice->Present( NULL, NULL, NULL, NULL );
}
